25821891 has 12 divisors (see below), whose sum is σ = 37568440. Its totient is φ = 17089920.

The previous prime is 25821883. The next prime is 25821899. The reversal of 25821891 is 19812852.

It is an interprime number because it is at equal distance from previous prime (25821883) and next prime (25821899).

It is not a de Polignac number, because 25821891 - 2³ = 25821883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25821899) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9070 + ... + 11571.

Almost surely, 2^25821891 is an apocalyptic number.

25821891 is a deficient number, since it is larger than the sum of its proper divisors (11746549).

25821891 is a wasteful number, since it uses less digits than its factorization.

25821891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20786 (or 20783 counting only the distinct ones).

The product of its digits is 11520, while the sum is 36.

The square root of 25821891 is about 5081.5244759816. The cubic root of 25821891 is about 295.5715854638.

The spelling of 25821891 in words is "twenty-five million, eight hundred twenty-one thousand, eight hundred ninety-one".